In stand up comedy, there can be a thin, easily crossed line between aggressive hilarity and remarks that are racist, sexist or anti-Semitic. A great performer needs to identify and respect these limits. Is it also possible for a painter to go too far? People used to think that Francis Picabia had done so with his ‘bad paintings’, works that inspired David Salle in the 1980s. But now Picabia, and maybe also Salle, belong to the postmodernist canon. Many commentators felt that Giorgio de Chirico, in his later works depicting gladiators and horses, had gone off the deep end, losing touch completely with the inspiration of his haunting early cityscapes. But nowadays it seems unacceptable for retrospectives to include only his early and widely admired masterpieces. The lessons of art history teach critics who reject the transgressive to take care.

Forty years ago Malcolm Morley became famous for his photorealist paintings. Then he had a long, highly successful career, demonstrating an amazing ability to work in a variety of disparate styles. In the 1980s, for example, he was identified as an important Neo-Expressionist. Now, in pictures completed in the three years before his recent death, Morley shows close focus pictures of armored knights. In Piazza d’Italian with French Knights (2017) two knights find themselves in a de Chiricoesque cityscape; in Melee at Agincourt (2017), a canvas of six by nine feet, a crowded field of mounted knights is on a yellow monochromatic background. And French and English Knights Engaged in Mortal Combat (2017) shows a joust in front of a lovingly detailed castle, with a sailing ship in the background. The great plaids in Italian Knight (2016) may recall modernist grids. And the vast green and yellow fields behind the knights in Tilting (2017) might remind you of the backgrounds in Alex Katz’s classic portraits.

Like many boys, Morley loved playing with toy soldiers – in the exhibition catalogue Nicholas Serota notes that his art demonstrates “the way we retain deep in our memory visual triggers to our profound psychological experiences, to our encounters with each other, and our relationship with the material world around us.” Via Paolo Uccello’s Niccolò Mauruzi da Tolentino at the Battle of San Romano (1438-40), the nineteenth-century Scottish history painter James Henry Nixon, and Lawrence Olivier’s 1944 film Henry V, Morley learned how to compose battle scenes.

However bizarre new artworks appear, it’s always possible to adduce sources and argue that they extend visual tradition, in a meaningful way. But for me, these new Morleys stand to history painting the way Liberace’s Chopin stands to normal pianists’ performances. Most of these pictures are absurd, so obviously, deeply silly that I cannot imagine an art world in which they would be taken seriously. Still, I grant that one painting is a real achievement. In The Ultimate Anxiety (1978), the second largest work in the show, a line of freight train cars runs diagonally across the Venetian lagoon, which is filled with gondolas and a golden ceremonial barge, with Venetians observing from the quayside. When in the 1840s a train bridge was built in Venice, John Ruskin worried that his favorite city had been ruined. Morley’s visual commentary, is an inspired update of an, alas, all too real concern for the fate of Venice. One could say, I believe, that the painting makes a fantasy out of Ruskin’s fear. But after that, I think, Morley went too far.